Adding domain users

I recently promoted a server to a domain controller. There are three other DC’s in my network, all are at different locations. When I try to add a user on my server I get an error message, “Windows cannot add the object because the Directory Service was unable to allocate a relative identifier”. I can “Connect To A Domain Controller” and specify one of the other DC’s in the network and add the user OK. The changes are reflected on my server so it appears that replication is working. Why can’t I add users on my DC and have it replicate to the other DC’s instead of having to add the user on another DC and have it replicate to my DC.